Optoelectronic waveguiding device and optical modules

Abstract

An optical transmission device suitable for a high-speed and large-capacity optical transmission system. An optoelectronic waveguiding device including an optical waveguide layer and cladding layers each having a larger band gap than that of the optical waveguide are deposited above and beneath the optical waveguide layer formed on a semiconductor substrate. The waveguide and cladding layers comprise optical waveguides each having a MQW structure in a direction of a light propagation axis of the optical waveguide layer. Among these optical waveguides, there exists first and second optical waveguides, whose layer structures may be mutually different. The optoelectronic waveguiding device maybe characterized in that an optical waveguide made of a bulk crystal exists in a connection part between the MQW structure waveguides each having a different layer structure. The specific connected optoelectronic waveguiding device elements may include semiconductor lasers, modulators and/or amplifiers.

1. A method for manufacturing an optoelectronic waveguiding device, comprising the steps of:
 forming a first optoelectronic device element on a semiconductor substrate;  
 applying a first resist layer to said first optoelectronic device element;  
 etching said first optoelectronic device element;  
 forming a second optoelectronic device element in said etched area on said semiconductor substrate;  
 applying a second resist layer;  
 etching said second resist layer to remove a crystal defect formed between said first and second optoelectronic elements; and  
 forming a waveguide from a bulk crystal in said etched crystal defect area, wherein said waveguide from a bulk crystal optically connects said first and second optoelectronic elements.  
 
   
   
     2. The method of  claim 1 , wherein said first and second optoelectronic elements include MQW structures. 
   
   
     3. A method for manufacturing an optoelectronic waveguiding device, comprising the steps of:
 forming a first layered structure on a substrate, said first layered structure comprising a first optical confinement layer, a first MQW layer, and a second optical confinement layer;  
 forming a protection mask on or over said first layered structure in part which should become a first optoelectronic device element;  
 etching other than part where said protection mask has been formed, and thereby etched said first layered structure comprising a first optical confinement layer, a first MQW layer, and a second optical confinement layer at said other than part;  
 forming a second layered structure on said substrate which exposed by said selective etching process, said second layered structure comprising a third optical confinement layer, a second MQW layer, and a forth optical confinement layer, and said second layered structure being formed by a first butt-joint process;  
 forming a second mask that has an opening on said second layered structure in the vicinity of said first butt-joint portion, and removing said second layered structure which is not masked and is exposed, and then exposing said substrate; and  
 forming an third optical waveguide made of a bulk crystal over said substrate at said opening,  
 wherein each a first and second optical waveguides in said at least said first and second layered structures are connected to each other with said third optical waveguide.  
 
   
   
     4. A method for manufacturing an optoelectronic waveguiding device according to  claim 3 , wherein said first layered structures is a laser part and said second layered structure is a modulator part. 
   
   
     5. A method for manufacturing an optoelectronic waveguiding device according to  claim 3 , wherein said first layered structures is a modulator part and said second layered structure is a laser part.